This invention relates generally to an improved device for stabilizing the upper member of a plural-part housing for an underground shut-off valve.
The control valve associated with a branch line serving an individual gas or water consumer is commonly buried substantially below ground level proximate the main supplying the branch line. Access from ground level to such a valve may be had through a hollow housing or box surrounding the valve by means of a hand-operated rod insertable downwardly through the housing for engaging a valve operating member.
A common type of valve housing is characterized by discrete upper and lower tubular sections which are axially movable in a telescopic manner. While the primary function of the two-part housing is to provide access to an underground valve, its other important functions are to provide for easy adjustment of its top-to-bottom length and to isolate the lower housing section from any downward axial movement of the upper housing section after installation of the housing in the ground. It is contemplated that, as the housing is installed, the lower section will bear directly upon the main or some exterior surface of the valve itself; the upper section will telescope either inside or outside the lower member; and, the overall axial length of the telescoped sections will be adjusted so that the top end of the upper section and the access lid carried thereby will be at or very near ground level.
As typically constructed, the top portion of the upper member of a plural-part tubular housing is configured to have a radially enlarged head which terminates in a downwardly facing annular shoulder. As the excavation about the upper and lower sections is filled, this annular shoulder is underlain and supported by fill to establish the desired vertical position of the upper section. If a typical housing is installed in a street, sidewalk or driveway, a stable paving medium such as concrete or asphalt will surround the head formed on the upper section in vertically supporting relation thereto. On the other hand, should a housing be installed in a parkway or lawn area, vertical support for the upper section is provided solely by earth or other relatively unstable fill compressively embracing its outer cylindrical wall and underlying the aforementioned annular shoulder.
A longstanding problem is created when rain water, melt water or moisture from other sources softens, erodes or otherwise destabilizes the fill embedding the upper housing section. In this situation, the upper section of the housing is likely to settle in the moistened fill under its own weight or due, perhaps, to some casual force applied to the top of the housing or to the access lid carried thereby. In aggravated occurrences of fill destabilization, the upper section may be displaced downwardly to such an extent that its top surface as well as the access lid are situated well below ground level. Thereafter, pooling of water in the crater formed around the upper section accelerates erosion and exacerbates the sinking problem. Moreover, once the upper section sinks below ground level, its top end may become overlain with enough earth to support vegetative growth which thrives due to favorable conditions for composting of leaves and grass clippings trapped in the depression formed about the sunken valve housing. When the upper housing sinks and becomes obscured by earth, vegetation or both, visual location of the access lid becomes difficult if not impossible. The time expended by utility company personnel to locate, clear and remove such a fouled access lid is obviously increased. Even greater cost and customer inconvenience are involved in excavating and repositioning a sunken valve housing. Dangerous, perhaps deadly, consequences arise in case an access lid for a gas valve in a branch line serving a burning structure cannot be quickly located by utility company personnel or firefighters.
If a single-piece valve housing is substituted for a telescopic housing to forestall sinking of its access lid, erosion about the upper end of the housing and creation of a crater therearound may result in projection of the upper end of the housing above the adjacent terrain. Also, in accordance with the teaching of the prior art, the upper segment of a two-part housing could include a radially projecting flange or the like adjacent its underground end to provide vertical support should the fill be eroded away about the housing's upper end. In either case, the resulting above-ground projection of a valve housing has potential for personal injury and catastrophic damage to power-driven lawn care equipment.
The somewhat pertinent U.S. Pat. No. 4,475,844 issued to Arntyr et al shows a tubular drain pipe vertically positioned in the ground with a tubular neck of an overlying drain cover telescopically received in the top of the drain pipe. An annular support is coaxially seated upon the extreme upper end of the drain pipe and has a flange which extends radially from the top of the drain pipe a substantial distance. The entire flanged support is buried or anchored in the ground some distance below the drain cover. The stated purposes of the disclosed support are as follows:
1. The support flange improves the vertical supporting ability of the material (earth) immediately underlying the drain cover. PA0 2. The support flange will deflect ground water radially away from the drain pipe to prevent softening of the ground layer surrounding the same. PA0 3. If the exposed surface surrounding the drain cover should sink, the flange will be pressed downwardly against the top of the drain pipe to prevent any tendency of the drain pipe to heave upwardly. PA0 4. In the case of light weight plastic drain pipes, the flanged support will be pressed downwardly by overlying earth against the upper end of the drain pipe to prevent its upward movement due to geostatic pressure.
While placement of the water-deflecting flange underground and below the drain cover is required for carrying out all the multiple purposes of the Arntyr et al invention, such placement of this type of support is not appropriate or useful in addressing the long standing valve housing problem outlined above. Destabilization of the upper housing section due to water entering around its exposed top end will not be prevented by a water-deflecting flange buried deep enough to rest upon the extreme upper end of the lower section of a two-part housing. Rather, what is required is a water-deflecting means which directs water away from the ground surface area surrounding the upper section thereby preventing softening and erosion of the fill that vertically supports the upper section.